We propose to develop and test a tongue brain-machine interface (BMI) capable of sufficiently enhancing quality of life (QoL) of blind persons to be valuable assistive technology. Investigation will be carried out along 4 interrelated lines: 1- Optimization of the technology;2- Psychophysical investigation of the match between TVSS system and perceptual capabilities of users;3- Investigation of changes in perceptual motor processes and capabilities of users. 4- Monitoring and analysis of usage, challenges, and opportunities the system may afford users. Studies on 1 will be carried out in Madison. Studies on 2 will be conducted at Harvard University in Boston, where the program of psychophysical assessment will address a number of aspects of visual perception with the simulators and will also assess changes that might occur in these functions with moderate level of adaptation to the device. The program will include basic testing aimed at determining the level of pattern vision provided by the system in ways similar to testing of basic visual function in observers starting with static stimuli generated by the computer, as well as full function assessments enabling the user to combined all of the flexibility and active exploration provided by head mounted camera in a simulated environment. Studies at the University of Wisconsin, Milwaukee will address areas 3&4 to determine the way a wearable TVSS influences the actions of the wearers from very controlled motor control assessments to Orientation and Mobility (O&M) and societal participation measures. Pilot data shows that TVSS users develop new perceptual motor skills in the first few hours of training. The population of active and adventuresome adults, while least likely to experience QoL changes, will be the most demanding consumers encountering a large variety of challenges for use of the system. Ongoing evaluation of usage and problem solving will be conducted with Ecological Momentary Assessment (EMA) using cellular phones with PDA capabilities. This will allow for compliance or usage tracking, contingent sampling and purposive sampling throughout the study on each wearer, allowing the iterative process necessary for optimization of the system. The study of the capacity of motivated blind persons to extract meaningful information with frequent use of a wearable, user friendly and slightly higher resolution version of the present system will occur in parallel with the technology optimization and psychophysics.